Signal system for telephones and the like



July 15 1924. v 1,501,694

r 'F. H. N. WOHLERS SIGNAL SYSTEM FOR TELEPHONES AND THE LIKE Filed April 14 1921 2 Sheets-Shes}. 1

I I i l Jul 15 1924.

F. H. N. WOHLERS SIGNAL SYSTEM FOR TELEPHONES AND THE LIKE Filed April 14 1921 2 Sheets-Sheet 2 NVENTOR.

Patented July 15, 1924.

UNITED STATES FRIEDRICH H. N. WOHLERS, 0F JAMAIC PRODUCTS CORPORATION,

A, NEW YORK, ASSIGNOR TO DICTOGRAPH A CORPORATION OF VIRGINIA.

SIGNAL SYSTEM FOR TELEPHONES AND THE LIKE.

Application filed April 14, 1821.

To all whom it may concern:

Be it known that I, FRIEDRICH H. N. WoHLEas, a citizen'of the United States, residing at Jamaica, in the county of Queens and State of New York, have invented certain new and useful Improvements in Signal Systems for Telephones and the like, of which the following is a full, clear, and exact description.

This invention relates to signaling means and particularly to telephone systems involving one or more stations, hereinafter referred to as minor stations which may or may not be made (part of an intercommunieating. system, an also one or more additional stations, hereinafter referred to as master stations. The master stations each have a loud speaking receiver and a private or individual connection to every other station with which they are connected. The master stations are commonly installed only in the offices or rooms of the executives or highest oflicials, and it is often desirable that a party calling from those stations know whether or not the signal at the called station is operating.

An object of the invention is to provide a telephone or signal system in which the operation of the signal devices at the called minor stations will be indicated at the calling master stations, and which is simple and readily adaptable to present telephone and signal systems with a minimum of changes in circuits and apparatus. Other objects and advantages will be apparent from the following description and the novel features of my invention will be particularly pointed out in claims.

In carrying my invention into practice, I include in the ma-incircuit a relay and place an audible or buzzer signal circuit that is closed by the relay in an inductive relation to the main signal circuit from the master station, so that the operation of the buzzer or audible signal will, by induction, create a fluctuation of the current in the circuit from the receiver of the master station and set up in the receiver vibrations corresponding to the operation of the buzzer or audible signal. The preferred mode of applying this principle is to include in the buzzer circuit a portion of the circuit from the receiver to the relay and including the relay, so that the making and breaking of the buzzer circuit by the operation of the buzzer will, due

Serial No. 461,281.

to the induction set up in the relay, cause corresponding fluctuations in the current through the loud speaking or other receiver and thus indicate to the party at the master or calling station that the audible signal at the minor or called station is operating properly. For a more complete explanation of the details which I may employ in the practice of my invention, reference may be had to the following description of embodiments of the invention.

In the accompanying drawing,

Fig. 1 is a diagram of an intercommunieating system showing two master and two minor stations, and having my invention embodied therein;

Fig. 2 is a diagram of the connections between a master station and a minor station with many of the circuits not particularly concerned in the invention omitted to better show the principle of the invention and which also illustrates a simple telephone system between two stations in which the inventionis embodied; Fig 3 is a simplified diagram of the calling circuits between two master and one minor stations;

Fig. 4 is a simplified diagram of a slight modification of the circuits, and

Fig. 5 is a diagram of the application of the principle of the invention to a simple telephonic signaling system.

Inasmuch as one of the contemplated applications of 'my invention is to intercommunicating telephone systems similar to that disclosed in U. S. Patent No. 1,160,125 I will now describe such an application of the invention and also explain its application to relatively simple systems.

Referring to Figs. 1 and 2 and particularly to Fig. 1, the master stations A and B are included in an intercommunicating system having minor stations X and Y. Each master station is provided with a loud speaking receiver 1, an ordinary receiver 2, and a switch hook 3 normally supporting the ordinary receiver to keep the talking circuit connected through the loud speaker 1 and operable upon lifting of the ordinary receiver therefrom to disconnect the loud speaker and connect the ordinary receiver into the talking circuit. Each master station is also provided with a plurality of switches 4, 5 and 6, which correspond with the other stations to which that particular station is connected, it

being understood that the number of switches at any master station equals the number of other stations to which it may be connected. The master stations also each have a sensitive transmitter 7, an audible signal comprising a bell or buzzer 8, a talking battery 9, a local buzzer battery and a plurality of relays 11 for operating visual signal indicators 12, one relay and visual signal indicator for each switch 4, 5 and 6.

Each of the illustrated minor stations is provided with a transmitter 13, a receiver 14, retardation coils 15, an audible signal 16, a relay 17 controlling a switch element 18, one or more visual signals 19 such as electric lamps, one lamp corresponding to each master station with which the minor station is connected, and a plurality of switches 20, 21, 22, 23, 24, 25, etc., one switch for each other station with which the particular minor station is connected. A battery T supplies the necessary current for communication from one minor station to another minor station. A battery R supplies the necessary current for operating the audible signals at each of the minor stations, the one battery being connected in multiple with the audible signal circuits of each of the minor stations. A battery R supplies the necessary current in a similar manner for the visual signal cir cuits at each of the minor stations.

The circuits will them under various operative conditions,

Let it be assumed that a party at master station B desired to call minor station Y. The calling operation consists in merely operating the switch 4 that corresponds with station Y and controls the connections leading thereto from this master station. The current will now flow from battery R through wires 26, 27, 28, relay 1?, wire 29. visual signal lamp 19 corresponding to station B, wire 31 to contact 32 of switch 21. then since the switch is in its normal posi tion to opposite contact 33, thence through wire 34 to contact 35 of switch 4, then, be cause the switch is closed. to opposite contact 36, wire 37 to switch hook 3. loud speaker 1, wires 38 and 39 to master station talking battery 9, through this battery, wires 40, 41. 42, 48 back to the opposite side of battery R The current passing in this circuit will energize relay 17 and. cause the latter to operate switch element 18 into engagement with contact 44 and close the circuit of the local buzzer or audible signal device 16.

The buzzer or audible signal circuit may be traced by starting with the positive side of battery B, through wires 45, 42. 43, negative side of battery R through battery R wires 26, 27, 28, relay 17, of station Y. wire 29, branch wire 46, contact-44, switch element 18, wire 47, switch hook 48 of the minor station Y, wire 48 to buzzer 16, wires be described by tracing 49, 50, 51 to the negative side of battery R. The audible signal is preferably a buzzer or hell which by its operation makes and breaks its circuit repeatedly, but it is to be under stood that the use of any audible signal device which when operating varies the current passing in its circuit is contemplated. It will be seen that the battery R and relay 17 are included within both visual and audible signal circuits, and the variations of the current in the audible signal circuit will cause a variation in the current passing through the relay. The inductance of the relay will, due to the fluctuations of the current therein, cause fluctuations in the visual signal circuit including the loud speaker or ordinary receiver so that the latter will emit sounds corresponding to the operations of the audible signal device or buzzer. The emission of a buzzing sound from the re ceiver during such a call will therefore be evidence that the audible signal device at the called station is operating properly since a failure of the buzzer to operate will leave the receiver circuit unaffected and no sound will be produced in the receiver.

To answer the call, the party at the called minor station operates his switch which corresponds with the visual signal lamp 19 that is effective, lifts his receiver and speaks in the usual way. In this case since station B is calling, the switch 21 at station Y which is adjacent the lighted lamp 19, is

operated. The operation of this switch will separate contacts 32 and 33 of the visual signal and relay circuit and thus open this circuit and cause deenergization of the relay. The deenergization of the relay allows switch element 18 to move away from contact 44 and open the audible signal circuit and silence the audible signal. or buzzer. The inclusion of the relay within the audible signal circuit will not cause the relay to lock itself closed since the opening of the circuit at each operation of the buzzer will cause the relay to be deenergized and release the switch element 18. The closing of the visual signal circuit is then necessary to again close or to hold closed the buzzer circuit. The lifting of the receiver from its hook at the minor station permits the hook to rise and open the audible signal circuit also. While it is only necessary to have the audible and visual signal circuits in inductive relation which might be accomplished for example by having the circuits in different windings on the core of the relay, I have found the use of a single winding to be satisfactory and less expensive.

The operation of the switch 21 in. answering the call, in addition to opening the visual, signal. circuit and silencing the audible signal device also establishes talking circuits as follows: From the positive side of battery 9 of the master station, current passes through wires 40, 41, 42, 52, contact. 53 of switch 21 at station Y, contact 54 (normally out of contact with 53 but, by reason of the operation of the switch, now in contact therewith), wire 55, branch wire 56, transmitter 13 at station Y, wire 57, contact 58 of switch 21, contact 59 (normally out of contact with 58 but, by reason of the operation of the switch, now in contact therewith) wires 60, 34, contacts and 36 (still closed), wire 37, switch hook 3, loud speaker 1 (or if the receiver switch hook 3 is up, caused by lifting the ordinary receiver, then through receiver 2 instead of 1) wires 38, 39, to negative side of battery 9. This completes a circuit from the trans mitter of the minor station Y to either of the receivers of the master station. At the same time another circuit is established from the positive side of battery 9 through wires 40, 41, 42, 52, contact 53 of switch 21 at station Y, contact 54, wire 55, branch Wire 61, receiver 14 of the minor station Y, wire 62, contact 63 of switch 21 at station Y, contact 64 of switch 21 (normally out of engagement with contact 62 but, by reason of the operation of switch 21, now in engagement therewith) wires 65, 66,. contact 67 of switch 4 at station B, contact 68 of the same switch (because switch 4 is still in operated condition) wires 69, and 70, to transmitter 7 of the master station E, wire 71, switch 6, wires 72 and 39 to the negative side of the battery 9. This completes a circuit between the receiver'of the minor station Y to the transmitter of the master station B, and it may be noted that the battery 9, wires 39, 40, 41, 42, 52, contacts 53 and 54, and wire are common to the two circuits.

At the conclusion of the conversation the party at station Y hangs up his receiver and restores switch 21 to its original condition, and the party at the master station B merely operates switch 4 back to its normal position. Similar circuits may be traced from master station B to any of the other minorstations. or from the other master stations to any of the minor stations, but to avoid confusion their detailed description will not be given herein since their circuits should now be obvious.

In Fig. 2 I have illustrated the essentials of the circuits between a master and a minor station so that the circuits may be more readily traced with the same reference characters. and also for illustrating the application of the invention to a simple system comprising one master and one minor station. The circuits are traced as above described.

It will be noted that only one audible signal circuit is necessary at each minor station when the latter is connected toa plurality of masterstations. To better illustrate the principle involved in such a case, reference may be had to Fig. 3, wherein the calling circuits and the audible signal circuit are illustrated, it being noted that the loud speaker of each master station and its corresponding visual signal 19 at each minor station are connected in parallel across the relay 17, as is also the local audible signal circuit.

The ring back in the embodiment herein described and illustrated is not incorporated in the circuits extending solely between the master stations or solely between the minor stations or from a minor to a master station, so that a detailed explanation of the calling circuits between those stations would appear to be unnecessary to an understanding of the present invention. If such an explanation is desired reference may be had to the U. S. Patent No. 1160125 hereinbefore referred to.

In Fig. 4 I have illustrated the simple circuits of a slightly modified system. in which. the separate battery in the audible signal circuit is eliminated. The use of the two batteries R and R is essential in the inter communicating system so that the circuits of Figs. 1 and 2 were adapted to the batteries used therein. Both batteries may be employed in a simple system, but where the audible signal circuit includes the battery and relay of the circuit between the master and minor stations, the battery R" may be eliminated and the connections arranged as in Fig. 4. The single battery is in such a case, the source of electrical energy to both the visual and audible signal circuits.

In Fig. 5 I have illustrated the invention as applied to a simple telephonic signalling system. A main circuit includes a controlling switch 73, a battery 74, a relay 75, and a loud speaker receiver 76. A secondary circuit has therein a switch 77 operated by relay 75, a winding in inductive relation to the relay, a battery and a buzzer. iVhen switch 73 is closed current will pass through loud speaker 76 and the relay. The energization of the relay will cause the switch 77 to be shifted to close the secondary circuit, and start the operation of the buzzer. The making and breaking of the secondary circuit by the operation of the buzzer will cause a fluctuating current to pass through the portion of the secondary circuit in inductive relation to the relay and by induction thereon produce fluctuations in the current through the main circuit. The latter will cause a buzzing sound to be emitted from the loud speaker or receiver 76 so that the person operating the key 73 will positively know that the buzzer is operating properly.

It will be obvious that various modifications and changes in the details and arrangements herein described and illustrated by way of explanation of the principle of the invention, may be made by those skilled in the art within the principle and scope of the invention.

I claim:

1. In a telephone system, a master station, a minor station, said minor station having a relay, a visual signal and an audible signal operable by making and breaking its own circuit, a circuit between the stations including the receiver of the master station, and the relay and visual signal of the minor station. a battery in said circuit, a second battery, a second circuit including the audible signal, the second battery, and a portion of the first named circuit including its battery and its relay, said second battery being connected in series with the first named battery and a switch device operable by the energization of the relay to close said second circuit.

:2. In a telephone system, two stations, one of said stations having a receiver, the other of the stations having a relay, a visual signal and an audible signal operable by producing a fluctuation in its circuit, a circuit between said stations includincr the receiver of said one station and the re ay and visual signal of the said other station, a battery in said circuit, a second circuit including said audible signal and a portion of the first named circuit including the relay, a battery in said second circuit and a switch device operable by the energization of the relay to close the second mentioned circuit.

3. In a telephone system, two stations, one of said stations having a single winding relay, the other of said stations having a receiver, a circuit between the stations including the relay and receiver, and means including an audible signal device and circuit controlled by the relay and including the relay winding in the circuit for varying the current in said receiver circuit to cause audible signals in the receiver corresponding to those of the signal device.

4. In a. telephone system between a called station and a callingstation, a talking circuit between the stations, a receiver in the circuit at the calling station and a trans mitter in the circuit at the called station, an electric signal device of the type which, during its operation, produces a fluctuation in its own operating current located at the called station, a local circuit for said signal device controlled by the talking circuit and arranged to vary the action of the talking circuit when said signal device operates, whereby the receiver will emit sounds during the action of the signal device, and a switc device at the called station active .upon said local circuit for rendering the signal de vice inactive independently of the talking circuit.

5. In a telephone system, two stations, a receiver at one of the stations, a single winding electromagnet at the other of the stations, a circuit between the stations including the electromagnet and receiver, alocal circuit, a signal device controlled by the local circuit, means operated by the electromagnet when energized by current in the first mentioned circuit for closing the local circuit to effect an operation of the signal device, said signal device being of the type causing a fluctuation in its own circuit dur ing its operation,said local circuit including the winding of the electromagnet whereby the fluctuations in the local circuit will, by induction, vary the current in the first men tioned circuit and cause the receiver to emit sounds corresponding to the operations of the signal. device, and means for rendering the signal device inactive independently of the circuit between the stations.

6. In a telephone system, two stations having a three wire talking circuit between them including a receiver at the calling station and a transmitter at the called station, a visual Signal and an audible signal at the said called station, the audible signal including means whereby it produces variations in its actuating current during its operation, a circuit for the visual signal bridged across two of the circuit Wires at said called station, a relay connected to the visual signal circuit to be energized concomitantly with the visual signal, a circuit for the audile signal under the control of the relay and. in inductive relation to the visual signal circuit whereby the operation of the visual signal by a completion of the circuit at the calling station between two of the talking circuit wires will cause an operation of the audible signal and. the latter by its inductive efi'ect upon the visual signal circuit will produce variations in the current passing through the receiver at the calling sta-- tion corresponding in frequency to the frequency of current in the variable signal, and switch means at the called station for open-- ing the bridged circuit to render the signal devices inefi'ective.

7. In a telephone system, two stations, a receiver at one of the stations, an electromagnet and visual signal at the other station, a circuit between the stations including a source of current, the electromagnet, the visual signal and the receiver, an audible signal device at the said other station operative by varying the current in its circuit, a circuit for the audible signal device including a source of current and a portion of the first named circuit containing the electromagnet, and means controlled by current in the first named circuit when the visual signal is made active for closing the circuit of the signal device to render it active.

8. In a telephone system, two stations, one of the stations including a transmitter, a relay, and a signal device operable by varying the current in its own circuit, the other station having a receiver, a talking circuit between said stations including the transmitter the relay and the receiver, a bat-- tery in said circuit, a second battery, alocal circuit including the signal device, the second battery and a portion of circuit between the stations including the relay, a switch device operable by the energization of the relay for closing the second circuit to render active the signal device, the operation of'the signal device causing variations in the current through the relay that due to induction cause similar variations in the circuit of the receiver and means for preventing fluctuations in the local circuit in order to remove its influence upon the talking circuit.

9. In a telephone system, two stations, one of the stations including a relay and a signal device operable by varying the current in its own circuit, the other station having a receiver, a circuit between said stations including the relay and the receiver, a battery in said circuit, a second battery. a second circuit including the signal device, the second battery and a portion of circuit between the stations including thtv relay and battery, the batteries being arranged to operate in series over the portion of the circuit between the stations. and a switch device operable by the energization of the relay for closing the second circuit to render active the signal device, the operation of the signal device causing variations in the current through the relay that due to induction cause similar variations in the circuit' of the receiver.

10. In a telephone system, a plurality of master stations, a minor station, a receiver at each master station. a plurality of visual signals, one corresponding to each master station at the minor station, a buzzer at the minor station, a circuit connection between the receiver at each master station and the minor station and including its corresponding visual signal, a common wire connecting the receiver to the opposite terminals of the connection and including therein a battery and a relay, a buzzer battery, an auxiliary circuit including the buzzer, buzzer battery and aportion of the common wire with the relay. and a switch device for said auxiliary circuit operated to closed position by the energization of the relay.

11. In a telephone system, a plurality of master stations, a minor station, a receiver at each master station, a plurality of visual signals, one corresponding to each master station at the minor station, a buzzer,'receiver and transmitter at the minor station. a circuit connection between the receiver at each master station and the minor station and including its corresponding visual signal, a common wire connecting the receiver to the opposite terminals of the connection and including therein a battery and a relay, a buzzer battery, an auxiliary circuit including the buzzer, buzzer battery and a portion of the common wire with the relay, a switch device for said auxiliary circuit operated to closed position by the energization of the relay, and switch mechanism at the minor station operable to break the circuit to the relay and substitute a connection to the receiver and transmitter of the minor station.

12. In a signal system, a main circuit having therein a battery, a telephone receiver, and a single winding relay, and a secondary circuit having therein a portion in inductive relation to the main circuit, a buzzer, and a switch device therefor controlled by the relay.

13. In a telephone system, two stations, a receiver at one of the stations, a signal device and a transmitter at the other of the stations, said signal device being operative by varying the current in its own circuit, a circuit for the signal device, a circuit between the stations normally including the receiver, a switch at each station, a source of current, and a control device for the circuit of the signal device, said device when the receiver circuit is completed by the switch at the receiver station, being effective to close the signal device circuit and render the signal device active, said circuits being in inductive relation whereby the variations in the current of the signal device circuit caused by its operation will, by induction, cause similar variations in the current in the circuit between the stations containing the receiver, said key at the station with the signal device when operated serving to interrupt the circuit through the control device and complete the circuit between the stations to include the transmitter.

14. In a telephone system, two stations, a receiver atone of the stations, an electromagnet and a transmitter at the other station, a'talking circuit between the stations including a. source of current, the electromagnet, the transmitter, and the receiver, a signal device at the said other station operative by varying the current in its own circuit, a local circuit for the signal device including a portion of the first named circuit containing the electromagnet, means controlled by current in the first named circuit for closing the local circuit of the signal device to render it active, and a switch device at said other station for connecting the transmitter and the relay alternately in said talking c1r cuit.

15. In a telephone system, a plurality of master stations, a minor station, a receiver at each master station, a plurality of visual signals, one corresponding to each master station at the minor station, a buzzer at the rumor statlon, a circult connect1on between the receiver at each master station and the minor station and including its corresponding visual signal, a common wire connecting the receiver to the opposite terminals of the connection and including therein a battery and a relay, an auxiliary circuit including the buzzer and a portion of the common wire with the relay and battery, and a switch device for said auxiliary circuit operated to closed position by the energization of the relay.

16. In a telephone system, a plurality of master stations, a minor station, a receiver at each master station a plurality of visual signals, one corresponding to each master station at the minor station, a buzzer, receiver and transmitter at the minor station, a circuit connection between the receiver at each master station and the minor station and including its corresponding visual signal, a common wire connecting the receiver to the opposite terminals of the connection and including therein a battery and a relay, an auxiliary circuit including the buzzer and a portion of the common wire with the relay, a switch device for said auxiliary circuit op-- erated to closed position by the energization menace of the relay, and. switch mechanism at the minor station operable to break the circuit to the relay and substitute a connection to the receiver and transmitter of the minor station.

17. In a telephone system, two stations having a three wire talking circuit between them including a receiver at the calling station and a transmitter and a switch in and normally interrupting one wire of the cir cuit at the called station, a signal device at the called station, a circuit for the device bridged across one of the talking circuit wires and the switch in another of the wires, said signal device when operative producing variations in current through the receiver, said switch being operative in one position to complete the signal device circuit through the two wires across which it is bridged and through the receiver and when in another position to render the signal device circuit ineffective and complete the talkin; circuit through the interrupted wire.

In witness whereof, I hereunto subscribe my signature.

FRlEDRlCH H. N. l VOHLERS. 

